The present invention aims to provide a highly reliable relief pattern detection device 1, including a slant FOP 3 having an input end surface 4 with which an object surface makes contact and an output end surface 5 substantially parallel to the input end surface 4, an irradiation light source 10 disposed on the output end surface 5 side of the slant FOP 3, for irradiating the output end surface 5 with light, and a CCD camera 11 disposed on the output end surface 5 side of the slant FOP 3, for detecting a relief pattern based on light emitted from the output end surface 5, in which optical axes Rf of optical fibers are inclined so as to create a first angle ± less than 90° in one direction from the output end surface 5 within a predetermined plane substantially perpendicular to the output end surface 5, the irradiation light source 10 irradiates the output end surface 5 with light in a direction to create a second angle ² less than 90° in the other direction from the output end surface 5 within the predetermined plane, and the first angle ± and the second angle ² are set so that light made incident from the output end surface 5 into a core 8 of the optical fiber 6 enters into a cladding 9.
